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Advantage of Common DC Bus Drive Systems

Posted by Justin Roberts on Feb 6th 2019

There are many advantages to common dc bus drive systems that allow for less upfront expense and a reduced cost of electricity to operate over the life of the system. These advantages make this design ideal for almost any instance that you have more than two inverters in an application. There are three specific areas in the design that allow for this reduced system cost which are reduced number of parts, reduced energy usage due to load sharing and a smaller overall dynamic brake as generally only one resistor is needed.

The first advantage is the reduced number of input line reactors and breakers needed for the system design. Instead of using three/single phase power to each inverter a single rectifier bridge is used to convert the AC power to DC. There is also less panel space needed due to the fact that most common dc bus drives allow for bookshelf mounting allowing for side by side mounting of the drives.
Load sharing happens automatically when you incorporate a common dc bus. What this means is that no energy is wasted to a dynamic brake on any individual motor but rather used by another motor in the system.

A dynamic brake is used to convert mechanical energy into heat via a resistor. This is needed for two reasons, the first is to limit the DC bus to a maximum potential so it doesn’t trip the drive and the second to allow the system to come to a stop in a timely fashion while not damaging equipment. With a common DC bus system only a single dynamic braking resistor is needed thus reducing the parts in the system even further.

When considering an upgrade or now system, give MES a call to discuss your best options going forward. Our Engineers will be happy to help you make the best decision for your need. 317-844-7328 or